Non–electrocardiographic (ECG)-gated computed tomography (CT) of the chest is one of the most commonly performed imaging studies. Although the heart is included in every CT study, cardiac findings are commonly underreported in radiology reports. Left ventricular size is one of the most important prognostic markers in multiple cardiac diseases and can be measured on almost all non–ECG-gated multidetector chest CT studies. This review will discuss the available evidence on different measurements of left ventricular size obtained on non–ECG-gated CT of the chest. Measurement thresholds, technical issues, and potential problems are emphasized, with practical recommendations.